import {
  document,
	window,
	HTMLCanvasElement,
	requestAnimationFrame,
	cancelAnimationFrame,
core,
	Event,
  Event0
} from "dhtml-weixin"
import * as THREE from './three/Three';
import { OrbitControls } from './three/addons/controls/OrbitControls.js';
import { VOXLoader, VOXData3DTexture } from './three/addons/loaders/VOXLoader.js';

import WebGL from './three/addons/capabilities/WebGL.js';
var requestId
Page({
  onShareAppMessage(){
    return getApp().onShare()
  },
  onShareTimeline(){
     return {title:"ThreeX 2.0"}
  },
	onUnload() {
		cancelAnimationFrame(requestId, this.canvas)
		this.worker && this.worker.terminate()
if(this.canvas) this.canvas = null
		setTimeout(() => {
			if (this.renderer instanceof THREE.WebGLRenderer) {
				this.renderer.dispose()
				this.renderer.forceContextLoss()
				this.renderer.context = null
				this.renderer.domElement = null
				this.renderer = null
			}
		}, 0)
	},
  webgl_touch(e){
		const web_e = (window.platform=="devtools"?Event:Event0).fix(e)
		this.canvas.dispatchEvent(web_e)
  },
  onLoad() {
		document.createElementAsync("canvas", "webgl2").then(canvas => {
      this.canvas = canvas
      this.body_load(canvas).then()
    })
  },
  async body_load(canvas3d) {


    if ( WebGL.isWebGL2Available() === false ) {

      document.body.appendChild( WebGL.getWebGL2ErrorMessage() );

    }

    let renderer, scene, camera, controls, clock;

    init();
    animate();

    function init() {

      renderer = new THREE.WebGLRenderer();
      renderer.setPixelRatio( window.devicePixelRatio );
      renderer.setSize( window.innerWidth, window.innerHeight );
      document.body.appendChild( renderer.domElement );

      scene = new THREE.Scene();

      camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 0.1, 1000 );
      camera.position.set( 0, 0, 4 );

      controls = new (window.platform=="devtools"?OrbitControls:OrbitControls0)( camera, renderer.domElement );
      controls.autoRotate = true;
      controls.autoRotateSpeed = - 1.0;
      controls.enableDamping = true;

      clock = new THREE.Clock();

      // Material

      const vertexShader = /* glsl */`
        in vec3 position;
        in mat4 instanceMatrix;

        uniform mat4 modelMatrix;
        uniform mat4 modelViewMatrix;
        uniform mat4 projectionMatrix;
        uniform vec3 cameraPos;

        out vec3 vOrigin;
        out vec3 vDirection;

        void main() {
          vec4 mvPosition = modelViewMatrix * instanceMatrix * vec4( position, 1.0 );

          vOrigin = vec3( inverse( instanceMatrix * modelMatrix ) * vec4( cameraPos, 1.0 ) ).xyz;
          vDirection = position - vOrigin;

          gl_Position = projectionMatrix * mvPosition;
        }
      `;

      const fragmentShader = /* glsl */`
        precision highp float;
        precision highp sampler3D;

        uniform mat4 modelViewMatrix;
        uniform mat4 projectionMatrix;

        in vec3 vOrigin;
        in vec3 vDirection;

        out vec4 color;

        uniform sampler3D map;

        uniform float threshold;
        uniform float steps;

        vec2 hitBox( vec3 orig, vec3 dir ) {
          const vec3 box_min = vec3( - 0.5 );
          const vec3 box_max = vec3( 0.5 );
          vec3 inv_dir = 1.0 / dir;
          vec3 tmin_tmp = ( box_min - orig ) * inv_dir;
          vec3 tmax_tmp = ( box_max - orig ) * inv_dir;
          vec3 tmin = min( tmin_tmp, tmax_tmp );
          vec3 tmax = max( tmin_tmp, tmax_tmp );
          float t0 = max( tmin.x, max( tmin.y, tmin.z ) );
          float t1 = min( tmax.x, min( tmax.y, tmax.z ) );
          return vec2( t0, t1 );
        }

        float sample1( vec3 p ) {
          return texture( map, p ).r;
        }

        #define epsilon .0001

        vec3 normal( vec3 coord ) {
          if ( coord.x < epsilon ) return vec3( 1.0, 0.0, 0.0 );
          if ( coord.y < epsilon ) return vec3( 0.0, 1.0, 0.0 );
          if ( coord.z < epsilon ) return vec3( 0.0, 0.0, 1.0 );
          if ( coord.x > 1.0 - epsilon ) return vec3( - 1.0, 0.0, 0.0 );
          if ( coord.y > 1.0 - epsilon ) return vec3( 0.0, - 1.0, 0.0 );
          if ( coord.z > 1.0 - epsilon ) return vec3( 0.0, 0.0, - 1.0 );

          float step = 0.01;
          float x = sample1( coord + vec3( - step, 0.0, 0.0 ) ) - sample1( coord + vec3( step, 0.0, 0.0 ) );
          float y = sample1( coord + vec3( 0.0, - step, 0.0 ) ) - sample1( coord + vec3( 0.0, step, 0.0 ) );
          float z = sample1( coord + vec3( 0.0, 0.0, - step ) ) - sample1( coord + vec3( 0.0, 0.0, step ) );

          return normalize( vec3( x, y, z ) );
        }

        void main(){

          vec3 rayDir = normalize( vDirection );
          vec2 bounds = hitBox( vOrigin, rayDir );

          if ( bounds.x > bounds.y ) discard;

          bounds.x = max( bounds.x, 0.0 );

          vec3 p = vOrigin + bounds.x * rayDir;
          vec3 inc = 1.0 / abs( rayDir );
          float delta = min( inc.x, min( inc.y, inc.z ) );
          delta /= 50.0;

          for ( float t = bounds.x; t < bounds.y; t += delta ) {

            float d = sample1( p + 0.5 );

            if ( d > 0.5 ) {

              color.rgb = p * 2.0; // normal( p + 0.5 ); // * 0.5 + ( p * 1.5 + 0.25 );
              color.a = 1.;
              break;

            }

            p += rayDir * delta;

          }

          if ( color.a == 0.0 ) discard;

        }
      `;

      const loader = new VOXLoader();
      loader.load( 'models/vox/menger.vox', function ( chunks ) {

        for ( let i = 0; i < chunks.length; i ++ ) {

          const chunk = chunks[ i ];

          const geometry = new THREE.BoxGeometry( 1, 1, 1 );
          const material = new THREE.RawShaderMaterial( {
            glslVersion: THREE.GLSL3,
            uniforms: {
              map: { value: new VOXData3DTexture( chunk ) },
              cameraPos: { value: new THREE.Vector3() }
            },
            vertexShader,
            fragmentShader,
            side: THREE.BackSide
          } );

          const mesh = new THREE.InstancedMesh( geometry, material, 50000 );
          mesh.onBeforeRender = function () {

            this.material.uniforms.cameraPos.value.copy( camera.position );

          };

          const transform = new THREE.Object3D();

          for ( let i = 0; i < mesh.count; i ++ ) {

            transform.position.random().subScalar( 0.5 ).multiplyScalar( 150 );
            transform.rotation.x = Math.random() * Math.PI;
            transform.rotation.y = Math.random() * Math.PI;
            transform.rotation.z = Math.random() * Math.PI;
            transform.updateMatrix();

            mesh.setMatrixAt( i, transform.matrix );

          }

          scene.add( mesh );

        }

      } );

      window.addEventListener( 'resize', onWindowResize );

    }

    function onWindowResize() {

      camera.aspect = window.innerWidth / window.innerHeight;
      camera.updateProjectionMatrix();

      renderer.setSize( window.innerWidth, window.innerHeight );

    }

    function animate() {

      requestId = requestAnimationFrame( animate );

      const delta = clock.getDelta();
      controls.update( delta );

      renderer.render( scene, camera );

    }
  },
})